The present invention relates generally to a conveyor.
A conveyor is known from SU 1 488 216 A1. According to FIG. 1 of SU 1 488 216 A1, the conveyor includes a plurality of endless conveying means in the form of leaf chains. The conveying means have a conveying section with a conveying surface on which conveyed goods 7, 8 can be transported. The conveyed goods are carried along by the conveying means with frictional engagement. The endless conveying means is held on a frame 1 using a plurality of rotatable deflection rollers 3, 4, 5, thereby enabling it to rotate endlessly. According to FIG. 2 in SU 1 488 216 A1, a driving wheel 12 having a rotary axle 11 is provided, the driving wheel 12 being coupled to the conveying means such that it be set into rotational motion by the conveying means. The rotary axle of the driving wheel is connected to a damping device 13, 14, 15, thereby enabling vibrations in the rotation of the conveying means to be damped.
Vibrations of that type occur mainly with long conveying means that include members having low stiffness. They have a low natural frequency under their own weight and, in particular, when tension is applied in the pulling direction of the drive; this natural frequency can be easily excited to become natural vibrations as a result of changing frictional conditions along the chain guidance. This is also referred to as stick-slip vibrations in this context.
The damping device described in SU 1 488 216 A1 includes an impeller 10 that runs in a viscous fluid 14, for example, oil, wherein the viscous fluid is accommodated in a closed chamber 13.
The disadvantage of this damping device is that it dampens the desired conveyance motion of the endless conveying means in addition to undesired oscillating motions. The drive of the conveying means must therefore be designed to be unnecessarily powerful. At the same time, a great deal of frictional heat is produced in the damping device, which heats up the damping device considerably, in particular when the conveying means move at high speed.
A further conveyor is known from EP 664 261 B1. In that case, the stick-slip vibration is ameliorated by a large damping mass. The above-described problem of frictional heat does not occur in this case. The disadvantage of this damping device is that the damping mass requires a great deal of space.